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"The Rainbow: Principles of Light and Shapes Between Forms, has been underway for a decade — understandably, since a rainbow can’t be an easy thing to produce. The artist enlisted the help of irrigation and rainwater-harvesting experts, atmosphere scientists, plumbing and electrical experts and Bemis Center staff to devise a rainwater and renewable energy system at the museum. The whole thing works on a massive scale: Rainwater is filtered and collected in six 10,500-gallon waters tanks. A custom-designed pump in the gallery then sends pressurized water to nine nozzles mounted on the museum’s roof, and twice a day, a wall of water rushes up above the building. Rainbows emerge within the walls of water, lasting for about 20 minutes each."